Variation of the substitution pattern of the Siamese-twin porphyrin (STP), an expanded porphyrin incorporating two pyrazole moieties, identified a set of substituents that result in an optimized preparation of highly crystalline products. The substituents have only negligible electronic and structural influences on the free base macrocycles and their dicopper complexes. Additionally, a new class of dinuclear iron complexes of the Siamese-twin porphyrin has been established. The homo- and heterobimetallic iron complexes of the STP were structurally characterized and showed to be pure intermediate spin in EPR spectroscopy and magnetic susceptibility measurements but remarkably gave two doublets in Mößbauer spectroscopy.
Keywords: Porphyrinoids; Expanded Porphyrin; Mößbauer; Intermediate Spin; Iron Complexes
